For several years, a formulation containing a proteolytic enzyme (chymopapain) has been utilized in extensive clinical trials in a surgical procedure, involving the injection of such a formulation into an intervertebral disk of the back, to relieve chronic back pain and other symptoms of disk disease, such as partial paralysis of the legs.
Recent references on the subject include the article by Kapasalis, et al. from the Journal of Laboratory and Clinical Medicine Vol. 83, pages 532-540 (1974); and pages 374-383 in the Journal of Neurosurgery Vol. 42, No. 4 (1975).
While the procedure has been very successful in its extensive clinical trial, it has an admitted disadvantage: approximately 1 percent of the patients which received the intervertebral injection with chymopapain solution suffer anaphylatic shock as a side effect. Furthermore, because of the danger of anaphylactic shock, it is at the present deemed inadvisable for a patient to receive more than one chymopapain intervertebral injection in his lifetime. Accordingly, the present expert judgment is that further problems with an intervertebral disk of the back in the same patient will have to be handled surgically. This is generally a very severe and sometimes dangerous procedure, which is accompanied by a separate group of potentially severe risks to the patient.
During the course of such a clinical trial, a double-blind study was administered by us, comparing a chymopapain-based back injection solution with a control injection solution, free of proteolytic enzymes.
Most suprisingly, the data indicated to us that the control solution, free of proteolytic enzymes, performed effectively in the cure of back pain, as did the chymopapain solution. These results were completely unexpected, and the physicians and scientists involved with the clinical trial were initially at a loss for an explanation.
This discovery is a significant advance in the art of injection solutions for intervertebral disk treatment, because a solution which is free of proteolytic enzymes, and is still effective, can achieve the desirable results of the prior art injection material with an extreme reduction in the risk of anaphylactic shock. Also, there appears to be no theoretical basis for limiting the use of the formulation of this invention to a single use in the lifetime of the patient. Accordingly, repeated treatment as necessary can be utilized by means of this invention.